The Internet Watch Foundation, Blighty's voluntary body for policing and filtering the 'net for child abuse images, has announced nearly 19,000 hashes of "category A" abuse images have already been stored in its new Hash List and distributed to major web firms.
The abuse images are sorted into categories A, B, and C, with "A" referring to the "worst of the worst".
The 19,000 hashes have been "given to five global internet companies [Facebook, Google, Microsoft, Twitter and Yahoo], who had volunteered to conduct a robust test on the list through their systems during the implementation period."
The hashes, created during the implementation stage, were sourced from images forensically captured on the Home Office Child Abuse Image Database, which in turn was sourced from police investigations.
Crucially, with the use of the hash list project, child sexual abuse images will be prevented from being uploaded in the first place, thus giving internet companies the power to stop people from repeatedly sharing the images on their services, said IWF.
The IWF Hash List has received a phased implementation since June 2015.
The organisation had stated its project will "automatically begin creating two types of hashes to meet the needs of the online industry. It will create PhotoDNA (technology developed by Microsoft) and MD5 hashes."
The organisation said it hopes that in the future, hashes will also be created from images that its analysts have sourced from reports and by "proactively searching for criminal content".
The IWF intends that its Hash List will become operational to all members in 2016. ®